Changes in Soil Carbon Dynamics in Response to Long-Term Soil Warming - Integration Across Scales from Cells to Ecosystems

Principal Investigator:

Melillo, Jerry

Institution:

MARINE BIOLOGICAL LABORATORY

Institution Address:

Woods Hole,
MA
02543-1015

Awarded Amount to Date and B&R Code :

FY 2013

$349 k

KP170201

DOE Program Manager:

Daniel Stover

BER Division:

Climate and Environmental Sciences

Research Area:

Terrestrial Ecosystem Science

Abstract Submit Date:

01/28/2014

Project Term:

09/01/2013 - 08/31/2016

Abstract:

Soils contain an estimated 2,500 Pg carbon (C), about three times as much as in the atmosphere as carbon dioxide and five times as much as in terrestrial vegetation in various organic carbon forms. A substantial fraction of the soil carbon occurs in relatively complex compounds. How the decay of these compounds will change in a warmer world is not clear. A major question in Earth System Science is: Will global warming accelerate the decomposition of these complex compounds by microorganisms, releasing carbon dioxide, a powerful heat-trapping gas, to the atmosphere, thereby creating a self-reinforcing (positive) feedback to the climate system? Put another way, will warming beget warming, with microorganisms as the central “actors?” This research will address this question by leveraging an ongoing climate-change experiment in which the soil in a 100-year old forest has been heated in situ, year-round for the past 22 years. Soil temperatures in the experimental plots have been raised 5 degrees Celsius above ambient temperatures in a deciduous forest stand at the Harvard Forest Long-term Ecological Research (LTER) site in central Massachusetts. Soils from the heated and control plots are being analyzed to evaluate both biogeochemical and microbial mechanisms of altered C cycling with warming on an ecological time scale. The study will employ a range of techniques including microbial genomics and compound-specific stable isotope analyses. Information gained from the study will be used to develop a new model of soil organic matter decay so that it represents the soil decay responses to climate change in a more mechanistic way.